Rotary engine.



No. 888,806. PATENTED MAY 26, 1908;

A. HOPKINS. v ROTARY ENGINE.

- n APPLICATION FILED' JULY 3o, 1906. BENEWED 00T.17. 1907.

5 SHEETS-SHEET l.

IPlmmmmmu xx l v PATBNTBD MAY 26 190s.l A, HOPKINS. ROTARY ENGINE. vAPPLICATION FILED JULYSO, 190B. BENEWED 00T.17. V1907.

No. 888,806. n PATENTED MAY 26, 1908.

A. HOPKINS.

ROTARY ENGINE.

`APPLIATION FILED JULY 30, 180B. RENEWBD 0012.17, 1907.l

5 SHEETS-SHEET 3y v la 'f l; (D in" Ill umn, n, c.

No. 888,806 P ATENTBD .MAY ze, 190s.

A A. EOPKINS.

ROTARY ENGINE.

LLLLLLLLLLLLLLLLLLLLLL 1906. RENEWBD 0OT.17, 1907.

EEEEEEEEEEEEE 5 UNITED STATES ALTON HOPKINS, OF DENVER, COLORADO.

ROTARY ENGINE.-

Specification of Letters Patent.

t Patented May 26, 1908i Application led July 30, 1906, Serial No.328,412. Renewed October 17, 1907. Serial No. 397,919.

T all 'whom it may concern.'

Be it known that I, ALToN HOPKINS, a citizen of the United States of.America, residing in the city and county of Denver and State ofColorado, have invented a new and useful Rotary Engine, of which thefollowing is a specification.

My invention relates to improvements in rotary engines, and the objectsof my invention are: First, to provide a rotary engine having a gateclosing steam port. Second, to provide a rotary engine having two indenpendent valve controlled steam inlets to opposite sides of the cylinderand pistons. Third, to provide a rotary engine having a high and lowpressure cylinder, containing pistons, a plurality of independent steamentrance ports, arranged at predetermined points in the circumference ofsaid cylinder, and a swinging gate valve in each cylinder, adapted toprevent a counter-pressure of steam on the pistons. Fourth, to provide arotary engine having a plurality of independent steam or other actuatingiiuid inlet ports, arranged at predetermined points around the innerperipheral surface of the cylinder. Fifth, to provide a double cylinderrotary engine arranged to use the exhaust steam of the high pressurecylinder expansively in the low pressure cylinder. Sixth, to provide acompound rotary engine, having a plurality of independent steam inletsinto the high pressure cylinder, and a plurality of exhaust ports in the-high pressure cylinder leading the exhaust steam from the high pressurecylinder to a plurality of steam inlets' on the low pressure cylinder,and a plurality of suitable exhaust ports in thelow pressure cylinderleading to the atmosphere. And seventh, to provide a compound rotaryengine provided with a plu rality of independent steam or otheractuating fluid inlet ports entering the high pressure cylinder atpredetermined points in its periphery, a plurality of exhaust ports insaid high pressure cylinder arranged to lead the exhaust from the highpressure cylinder into the low pressure cylinder, a swinging gate valvepivotally hinged at the entrance of each steam port of both the high andlow pressure cylinders, and provided witha plurality of automaticallyoperating independent rotary valves arranged to control each of saidports, and provided with an axial shaft carrying pistons securedthereto, and rotatably mounted in the cylinders of said coml poundrotary engine, and provided with pre-v n determinedly arranged steamimpact surfaces. I attain these objects by the mech-V anism illustratedin the accompanying drawings, in which:

Figure 1, is a horizontal sectional view of my improved rotary engine.Fig. 2, is a transverse, sectional view through the high pressurecylinder of the same. Fig. 3, is an end elevation of my rotary engine.Fig. 4, is a horizontal sectional view showing a modification of thevalve mechanism. Fig. 5, is a fragmental, sectional view of Fig. 4,showing a modification of the exhaust ports leading from the highpressure cylinder to the low pressure cylinder. Fig. 6, is an end viewof a modified form of the engine, in which the rotary valves aredispensed with, and the steam admitted through a port in the powershaft. Fig. 7, is a transverse, sectional view thereof, through the highpressure cylinder. And Fig. 8, is a horizontal, sectional view of thesame, on the line 8-8 of Figs. 6 and 7.

Similar letters of reference refer to similar parts throughout theseveral views.

Referring to the drawings, the numeral l, designates the base orfoundation plate of my engine 2, designates the casing, which may becast integral with the base plate, if desired. Thiscasing is preferablycylindrical in form, and is provided at its opposite sides withprojecting lug portions 3 and 4, which form steam chests, preferablyprojecting horizontally from it.\ The cylinder casing may contain onlyone piston cylinder and piston if desired, but I preferably illustratemy improved rotary engine with a high and low pressure cylinder withinone casing g consequently the casing 2 contains two cylinders 5 and 6.In the central portions of each of the steam chests 3 and 4, I formcircular apertures 7 and S. These apertures are provided withanti-friction bushings 7"4 and 8", and they are bored out to formjournal bearings for rotating valves and stems 9 and l0. The interiorsof the lugs are provided with steam inlet ports 9A and 9B and 10A and10B, which are separated from each other by a partition l1. posite thecylinders and lead directly into them, the ports 9^ and 9B on oppositesides .of the cylinder leading to `the high pressure cylinder 5, and theports 10A and l0B leading to the low pressure cylinder 6. Thecylindrical casing is preferably made with both of These ports arearranged op-v its opposite ends open, and with a partition 12 formed ata pr'edetermined point intermediate of its ends,thus forming acylindrical space on both sides of the partition. This partition isprovided with an axial bore 13, which contains an anti-friction bushingof brass or other suitable metal. This bushing 'forms a journal bearingfor a main piston driving shaft 141, which extends through bothcylinders in opposite directions from the partition, and extends throughthe cylinder heads 15 and 16, which are provided with outwardlyextending hubs 17 and 13, which are provided withbushings 19 and 20.These cylinder heads are secured to the ends of the casing, by anysuitable means, but preferably by cap screws 23. The steam enters thesteam chests 3 and 4, to the valve ports 9A and 9B, of the high pressurecylinder through the apertures 24 and 25, the entrances of which arethreaded to receive the threaded end of pipes, which lead to a supply ofsteam or other suitable motive fluid. Un the piston or driving shaft, Isecure a piston 26, which comprises a plurality of steam impactsurfaces, 26, which ht closely but rotatably between the cylinder headand the partition, and the inner peripheral surface of the cylindricalcasing. On the piston driving shaft, T also mount a second piston 26A,which is formed to fit the inner periphery of the cylinder 6, betweenits cylinder head and the partition. The opposite ends of these pistonsare curved in opposite directions from opposite sides of each pistonfrom about diametrical points through the lesser thickness and diameterof the piston to longest diameter of its ends, from which point straightsurface extends to about the center of the length of the piston. Thesepistons are secured to the piston shaft by any suitable means, but arepreferably securely keyed to them, and in the two opposite peripheraledges of the pistons l secure in any suitable manner packing material ofany suitable character, preferably illustrating a roller packing 27,which may be of any suitablev material, arranging it in semi-circularrecesses 2S, to bear against the inner peripheries of the cylinders. Andin order to insure a close bearing contact of the roller against theinner periphery of the cylinder, I provide each roller in the pistonwith a constant outward pressure, and preferably carry out this featureof my invention in the following manner: In each steam impact surface2613 of the piston, T form steam ports 27, which extend into the bottomof the recesses 28, in which the rollers are seated directly under theroller. The steam flowing into the cylj inder under pressure strikes theimpact surfaces of the piston and flows into these ports and forces theroller packings against the inner periphery of the cylinder. The steampressure in effect practically buoys up and holds. the roller packingsagainst the inner periphery of the cylinder, and they are free to eitherroll againstthe cylinder or slide against its surface, as the pistonsrotate. Tf desired the steam port may be dispensed with, and a resilientmember of any character may be placed in the recess 28 below the rubberrollers, and be arranged to hold the rollers with constant resilientpressure against the inner periphery of the cylinder, or the rubberrollers themselves may be made large enough relative to the recess, andthe inner surface of the cylinder, to bear against the cylinder withtheir own inherent elastic and resilient tension.

The steam inlet ports ar-e preferably arranged to enter the cylinders ona horizontal plane, but are extended circumferentially around the innerperipheral shell of the cylinders in the direction in which the pistonrotates a short distance, the ports being at this point an open recessin the inner peripheral surface of the cylinder, which is adapted toform a housing for the swinging valves 29 and 30, and 29A and 30A. Thesevalves are preferably made concavo-convex in form, and are pivotallysupported in curved recesses 31 and 32, formed in the edge of the portsat their junction with the cylinder, and also by tapering centers 33 and34, which are formed on the ends of cap screws 35 and 36, which arethreaded to threaded holes formed in the cylinder heads through whichthey extend, and on center points 37, and 38, which are formed on theopposite ends of pins 39, which are secured in the partition and projectfrom it into both cylinders. The ends of 'the valves are formed withtapering center recesses adapted to receive the tapering center pointsof the screws. The cap screws 35 and 36, are provided with check nuts40, to secure them in adjusted positions against accidentaldisplacement; consequently these swinging valves which I term gatevalves, swing out of the port recesses against the'sides of the piston,when steam is admitted from the valve into the port, and are pushed backinto the curved surface of the piston as they rotate, and when thesegate valves are closed, the ports are in a measure closed. They are usedto guide the steam above the horizontal centers of the pistons. Thesegate valves may -be dispensed with if desired, as the area of thecylinder above its horizontal center is so much greater than the areabelow the horizontal center' at the point of steam intake, and themovement of the piston is so rapid that their use while an advantage isnot absolutely necessary to the operation of the engine. l preferablyemploy them however, and in order to make their contacting points withthe piston practically steam tight, l provide their piston engaging 4ends with a suitable packing device or material, preferably forming aconcaved recess in the end of each gate valve, in which I place a roller42, which may be composed of any suitable or anti-friction material.

In the drawings I have preferably illustrated. my improved rotary enginewith two independent steam inlets, and two independent valves and steaminlet ports into the two cylinders from the valves, the valves and theirports being arranged on opposite sides of the cylinders; consequentlythe gate valves are arranged on opposite sides of both the high and lowpressure cylinders, and are preferably pivoted on a diametrical axialline of the horizontal plane of the cylinder and piston and pistonshaft, and they open and close synchronously in the high pressurecylinder and also in the low pressure cylinder, but in alternate orderfrom their action in the high pressure cylinder, as will be explainedmore fully hereinafter. The valves 9 and 10, are provided with steaminlet ports 43 and 43A and 44 and 44A, which register with the ports 9Aand 9B and 10-l and 10B as the valves rotate, and form a clear steamport passage from the steam inlet aperture of the valve chest throughthe valves ports to the valve gates and past them to the cylinders. Thevalves 9 and 10 are each provided with valve stem portions, whichproject through any suitable stuffing boxes, but which preferabiyconsist of the packing apertures 45, the packing 46, and the glands 47,which are preferably threaded to the packing apertures 45, the packing46, and the glands 47, which are preferably threaded to the packingapertures and are provided with a wrench receivingcollar portion 48, attheirl outer ends; the inner ends of the valves are preferably seated incupped bushing 49,

, which extends only partially through the rear wall of the casing,which is threaded to receive a thrust nut 50, by which the position ofthe ports of these valves may be set relative to the partition 11, andto their journal bearings. The forward ends of these valves are providedwith reduced neck portions 51, in which a divided ring collar 52, isloosely clamped, the collar being'formed on the end of a bracket 53,which'is secured to a flange 54, formed on the hub of the adjacentcylinder head. Upon the ends of the valve stems lI secure pinions 55 and56, and upon the end of the pistons shaft I also secure a gear 57, whichmay be made large enough in diameter to mesh with the pinions on thevalve stems, but I preferably interpose between the driving gear of theshaft and the pinions on the valve stems, idler pinions 5S and 59;consequently I make the pistons driving shaft gear of a diameter toallow the idler pinions to be interposed between it and the valve stempinions, and I support these idler pinions on a stud bolt 60, which issecured to theY flange 54 of the adjacent cylinder head.

In Fig. 4, which is a horizontal sectional view of the modification ofthe arrangement of thevalves and of the exhaust valve ports leading fromthe exhaust ports of the high pressure cylinder to the low pressurecylinder, the valves extend across the steam chest of the-high pressurecylinder only and terminate in the partition in the steam chest betweenthe two cylinders, an aperture 68 being formed in this partition whichdoes not extend quite through the partition, which is preferablyprovided with a bushing 69, in which the inner ends of the valves arerotatably seated, otherwise both valves are the same in every respect.Consequently in this arrangement the low pressure cylinder is notprovided with a valve controlled inlet port, but the exhaust steam fromthe high pressure cylinder flows directly into it from the exhaust portsof the low pressure cylinder, and I preferably arrange these exhaustports in this arrangement of the engine in the following manner: On theoutside of the casing of the low pressure cylinder I cast a port lug 70,in which ports 71 are formed, which register with the exhaust inletports 10A, and 10B of the low pressure cylinder, and these ports 71`register with ports 72 formed in the shell of the casing on .oppositesides of it, which intersect ports 61 and 62 of the high pressurecylinder. Consequently the exhaust steam from the high pressure cylinderflows directly into the opposite sides of the low pressure cylinder, anddoes not pass through the valves as shown in Figs. 1 and. 2.

Upon the opposite end of the pistons driving shaft, I secure a i'lywheel pulley 7 2A, from which power may be transmitted from the engineby belt. While the pistons may be secured to the driving shaft inalinement with each other, they are preferably secured. to the drivingshaft to stand in an angular position that will permit the low pressurecylinder to receive the exhaust from the high pressure cylinder theinstant the high pressure cylinder passes its exhaust ports, or they canbe positioned at the quarter or at right angles to each other. Thevalves 9 and 10, are also set with their ports standing to work inunison with this arrangement of the pistons.

The operation of my improved rotary engine is as follows: The steam orother motive fluid enters the steam inlet ports of the valve chests intothe ports 9A and 9, and as the valves are rotated the steam passesthrough their ports to the gate valves and forces them to swing openagainst the straight side of the high pressure cylinder piston, whichforces this piston to rotate as the steam pressure is applied to thestraight portions of its opposite sides at the same time, both above andbelow its horizontal centers, as shown by the arrows in Fig. 2;consequently it is driven l by two opposite steam pressures, and at ashort distance from the gate valves in the direction of the pistonsrotative movement,

exhaust ports 61 and 62 are formed through the casing, which areconnected to curved pipes 63 and 64, that extend from these exhaustports to steam inlet port apertures 65 and 66, that lead into the steaminlet ports 1()A and 10B, from which the steam flows through the ports43A and 44A of the valves 9 and 1() that lead to the low pressurecylinder, these ports being arranged relative to the ports 43 and 44, toadmit the steam to the opposite sides of the low pressure cylinder, thesame as it is admitted to the high pressure cylinder, and the gatevalves of the cylinder are opened by the steam and all of these valvesare closed by the curved portion of the pistons as they rotate and arepushed back into their port recesses until the pistons pass them andthey are again opened by the inilowing'steam. The rotation of thepistons rotates the driving shaft, and its gear, which in turn rotatesthe idler pinions and the idler pinions rotate the pinions on the valvestems.; consequently the valves are rotated in operative order to alwaysstart and to admit steam to operatively drive the pistons. Exhaust ports67 are formed through the shell of the casing to the atmosphere,preferably in alinement with the steam inlet ports. The steam from thehigh pressure cylinder is thus used expansively in the low pressurecylinder. lf desired two or more pairs of cylinders can be placed on onedriving shaft, or one low pressure cylinder and piston can be placedbetween two high pressure cylinders. p

ln Figs. 6, 7, and 8, 1 have illustrated a change in the construction ofthe engine, in the manner of admitting steam to the high pressurecylinder. ln this form of the engine, the rotary valves 9 and 10, aredispensed with, and the front cylinder head or bonnet 73, is formed witha longitudinal rib or projection 74, which extends from diametricallyopposite sides of the hub 17, and this rib is provided with a port 75,which opens into the hub, and also communicates with chambers or ports76 and 77, back of the gates 29 and 30. The power shaft 14A, is providedwith a transverse port 78, which registers with the port 75 in thecylinder head, and it is also provided with an axial port 79, whichextends from the forward end of the shaft, and intersects the port 78. Apipe flange 80, is bolted to the outer end of the hub 1.7, and isinteriorly threaded to receive a steam inlet pipe 81, which communicatesdirectly with the axial port 79. Thus, the steam will enter the port 79,and pass through port 78 to the port 75, in the cylinder head, andthence to the chambers 76 and v7 7 baclr of the gate 29 and 3() of thehigh pressure cylinder. The piston 26, will be revolved, and the exhauststeam will pass into the low pressure cylinder through ports 62, 72, and71, as previously described, and the supply of steam to the port 75 willbe intermittently cut oil', as the port 78, by the revolution oftheshaft, assumes a position at right angles to the port 75, or in otherwords, as the entrance to the port 75, is closed by the solid portion ofthe shaft.

My rotary engine is adapted for all of the general uses for which poweris required, and is especially adapted for use as a motor forautomobiles. lt is simple in construction, compact, light in weight, andsmall of size for the amount of its power; and while l have especiallydesigned my invention as a rotary steam or other expansive fluid engine,it is obvious that it can be used as an air compressor, and also as apump, and 1 contemplate the use of my invention as an air compressor andas a pump.

Having described my invention, what l claim as new and desire to secureby Letters Patent is:

1. In a rotary engine, the combination of a casing having a high and lowpressure cylinder, of a rotary piston in each cylinder, each pistonhaving two oppositely arranged steam impact surfaces, two oppositelyarranged and independent steam inlet ports leading into each cylinder,two independent rotary valves in said steam inlet ports controlling theports, ports to both cylinders, an exhaust port for each valvemechanism, and a high pressure cylinder connected to the steam inlet andvalve ports of said low pressure cylinder.

2. ln a rotary engine the combination with the casing, of the high andlow pressure cylinders separated by a partition, the steam chests onopposite sides of said casing, the independent steam inlet portsseparated by a partition, the independent rotary valves having portsarranged to admit steam in unison at opposite sides of each cylinder,and arranged to admit the exhaust steam of the high pressure cylinder ata predetermined time to the low pressure cylinder, the driving shaftextending axially through both cylinders, the oblong pistons havingopposite steam impact surfaces and -opposite curved ends, and steamimpact portion, a steam inlet swinging gate valve pivotally mounted atthe junction of each steam inlet port with the interior periphery ofeach cylinder, arranged to be opened by the inflowing steam pressure andto be closed by said curved back portions of said pistons, and means forrot ating said valves from said driving shaft.

8. In a rotary engine, the combination with the casing, the high and lowpressure cylinders, the cylinder heads, and the valve chests, arrangedon opposite sides of said cylinder, a pair of` rotating valves in saidvalve chests, each having ports adapted to admit steam to each cylinder,a main driving shaft axially mounted 1n said cylinder heads and casing,pistons comprising members having their opposite ends arranged to fitrotatably the inner periphery of said cylinders, and means includingports for conveying the-actuating fluid from the high pressure cylinderto the low pressure cylinder.

4. In a rotary engine, the combination with the casing having twocylinders therein, divided by a partition, the cylinder heads secured tosaid casing, the taper-center points insaid partition, the adjustablecenter-points in said cylinder heads, the valve chests on said casing,the steam inlet ports in said valve chests, and the curved recesses atthe junction of said. ports and the inner periphery of said cylinder,and swinging gate valves pivotally supported on said.

pivotal centers and in said recesses.

5. In a rotary engine, the combination of a casing, containing twocylinders, a piston rotatably mounted in each cylinder, a driving shaftsecured to said pistons, ports arranged to admit steam from a source ofsteam supply to one of said cylinders, ports arranged to lead the steamfrom the first cylinder and piston to the second cylinder and piston,two il'idepe'ndent steam admitting rotary `valves arranged to controlthe admittance of steam to said cylinders and pistons, and meansconnected with said main shaft and valves for rotating said valves.

6. ln a rotary engine, the combination of a casing, having a high and alow pressure cylinder separated by a partition, cylinder heads securedto the opposite ends of said casing, a shaft journaled in said partitionand cylinder heads, pistons secured to said shaft and rotatably mountedin each cylinder, two oppositely arranged and independent valve chestsalong both cylinders in said casing, two independent steam inlet portsin said high pressure cylinder, two independent rotary valves arrangedhaving steam passage ports rotatably mounted in each valve chest tocontrol said ports, two independent exhaust ports and exhaust pipesextending from said high pressure cylinder to said low pressurecylinder, steam inlet ports in said oppositely arranged independentvalve chests, two steam impact surfaces on opposite sides of each ofsaid pistons, two curved surfaces on opposite sides of each of saidpistons from said impact surfaces, independent swinging gate valvespivotally mounted in each of the ports, adapted to swing out against thecurved surfaces of said pistons, and to be moved by said pistons out oftheir paths as they rotate, and means for rotating said valvesto'operatively admit steam tol the piston of said high pressure`cylinder, and suitable exhaust ports in said low pressure cylinder.

7. In a rotary engine, the combination of the` casing having a high andlow pressure cylinder, a piston in each cylinder of Yoblong form, eachpiston containing a steam impulse surface and a curved surface, valvecontrolled steam inlet ports to said high pressure cylinders, a gatevalve pivotally hinged to swing from said ports against the curvedlsurface of said pistons, a packing roller in the free end of each gatevalve adapted to engage the surface of said pistons, an axial drivingshaft on which said pistons are secured in a predetermined angular relation to eachother, steam ports leading from said high pressurecylinder to said low pressure cylinder,` and suitable exhaust portsleading from said low pressure cylinder to the atmosphere.

8. In a rotary engine, the combination with a suitable casing having ahigh and low" der heads on the opposite ends of said cas-v ing, a pairof steam chests one on each side of said casing, a pair of steaminlet-ports on opposite sides of each cylinder, having a partitionbetween them, a steam inlet in each port of said high pressure cylinder,inlet apertures in each port of said low pressure cylinder, steamexhaust apertures in said high pressure cylinder, and steam exhaustpipes connected to the exhaust aperture of said low pressure cylinderand extending to the steam inlet apertures in the ports of said lowpressure cylinder, rotating valves extending through both cylinders andprojecting'beyond said casing, a driving shaft rotatably mounted in saidcasing and cylinder heads, a gear on said driving shaft, and meansincluding gears connected with said driving shafts gear forrotating-said valves.

9. In a rotary engine, the combination of the cylindrical casing havinga suitable foundation bed plate, two steam chests on said casing, a highand low pressure cylinder in said casing, two steam inlet ports on saidvalve chests and cylinders, an axial driving shaft, pistons secured onsaid shaft to stand at a predetermined angle relative to each other,valves vat the entrance of said ports into said cylinder adapted toprevent back pressure of infiowing steam on said piston, a rollerpacking between said pistons and the inner periphery of said cylinders,and means for conveying the exhaust steam from the high pressurecylinderto the low pressure cylinder, and the exhaust steam from the lowpressure cylinder to the atmosphere.

10. In a rotary engine, the combination of the casing containing aplurality of cylinders, a plurality of independent valve chests andvalves and ports for admitting steam at a plurality of differentpredetermined points in said cylinder, and an axial shaft having aplurality of pistons rotatably mounted in iro said cylinders, having aplurality of oppositely arranged steam engaging surfaces adapted toreceive steam synchronously from said plurality of ports, meansincluding a plurality of ports connecting said cylinders Vfor usingsteam expansively in said cylinders,

and means including gears connected to said axial shaft and valve foroperating said valves. f

1 l. In a rotary engine, the combination of the casing, having a highand low pressure cylinder, the cylinder heads, the driving shaft andpistons, the two steam chests, and the four steam inlet'ports, of thetwo valves on said cylinder heads, of pistons secured. .to said shaft tostand in said cylinders at a predetermined angle to each other, providedwith oppositely arranged steam impact surfaces, swinging valvespivotally hinged at the junction of said four steam inlet ports withsaid cylinder, oppositely arranged curved surfaces on each of saidpistons adapted to automatically close said valves as said pistonsrotate, a rotary packing between said valves and the curved surfaces ofsaid pistons, and a rotary packing between the periphery of said pistonsand the inner periphery of said cylinders.

13. In a rotary engine, the combination with the casing, of thecylinders therein, the steam chests, the pistons, the axial pistonshaft, and the steam inlet ports having a partition between them, thevalve seat bushings in said steam chest ports, the circular valvesrotatably mounted in said valve seat bushings, an adjustable thrust nutat one of said valves threaded to said steam chests, the diametricalports through said valves registering with the ports of said cylinders,the stuffing boxes in said steam chest surrounding said valves, meansincluding the idler and piston shaft gear and the valves gears forrotating said valves, and a collar on each valve arranged to take theopposite end thrust of said valves from said thrust nuts.

14. In a rotary engine, the combination with the casing, high. and lowpressure cylinders separated by a partition of said casing, the cylinderheads, the two valve chests, the

ports and in the inner periphery of said cylinder for said gate valves,the double pointed tapering centers in the dividing partitions betweensaid cylinders, the adjustable tapering centers in said cylinder heads,and the tapering center recesses in the ends of said gate valves.

15. In a rotary engine, the combination with the casing, of thecylinder, the pistons, the istons shaft, the four steam inlet ports foroth cylinders, the two valves, and the end thrust adjustable nuts andcollars for said valves, with a gear on said piston shaft, a gear oneach valve, and an idler gear in mesh with each valves gear, and in meshwith said pistons shaft gear.

16. In a rotary engine, the combination of compound cylinders integrallycombined in a cylindrical casing, a plurality of independent steam inletvalves arranged at predetermined points in the high pressure cylinder, arotary iston in each cylinder, a swinging gate va ve arranged to controlthe steam inlet port to the piston of said high pressure cylinder and tobe closed by said pistons rotative movement; independent exhaust portsextending through the shell of said cylinders from said high pressurecylinder to said low pressure cylinder, and swinging gate valvesarranged at the entrance of said exhaust ports into said low pressurecylinder, arranged and adapted to be closed by said low pressurecylinders piston.

17. In a rotary engine, a cylinder provided with cylinder headsandcontaining a pair of piston cylinders, a partition between saidcylinders, a shaft extending axially through said cylinder andpartition, and a piston in each cylinder secured to said shaft, swinginggates on diametrically opposite sides of ,each cylinder provided with arotary roller packing on their free ends, and a chamber back of eachgate, inlet ports communicating with the chambers of one cylinder; meansconnected with the shaft for intermittently closing said ports; andports connecting the two piston cylinders whereby the steam from onecylinder exhausts into and operatively drives the piston of the othercylinder.

In testimony whereof I affix mysignature in presence of two witnesses.

ALTON HOPKINS.

Iitnesses:

RICHARD MCKNIGHT, GEORGE II. SETI-IMAN.

